A PROCESS OF USING CARBOMER AS A DRUG CARRIER TO THE HARDER TISSUES OF THE ORAL CAVITY

Abstract

In this invention A PROCESS OF USING CARBQMER AS A DRUG CARRIER TO THE HARDER TISSUES OF THE ORAL CAVITY', a carbomer is used as a drug carrier, that can stick on to the harder tissues of the oral cavity. The carbomer carrying the drug ensures that the drug is directed towards the target site only and is formed by compressing under pressure the barrier material, i.e., Magnesium stearate in this case to about 0.5 to 0.7 mm thickness and about 8 mm diameter. Potassium oxalate or Strontium chloride is triturated and made into fine powder, subsequently mixed with the hygroscopic carrier material, i.e., carbopol under dry conditions. Readily available mixture of the drug and the carrier material together is compressed under pressure against the readied Magnesium stearate pellet, which gives rise to a single pellet of about 1.3 to 1.7 mm thick or as thin as possible.

Full Text

This invention, A PROCESS OF USING CABOMER AS A DRUG CARRIER TO THE HARDER TISSUES OF THE ORAL CAVITY' pertains to the use of a carbomer as a drug carrier to the harder tissues of the oral cavity. Till date, it has been established that carbomers can be used as drug carriers, only where the target site is soft tissue. However, this method provides a drug delivery system, wherein carbomer has been used as an adhesive to the tooth surface, i.e., the hard tissues of the oral cavity. It has been further established that carbomer is adhesive to the teeth and stays for quite a long period. Till now, the treatment of dentinal hyper-sensitivity has been focused on using mouthwashes, dentifrices, lasers, Iontophoresis and so on. The problem with dentifrices and mouthwashes are that they remain in contact with tooth structure only for short periods and thus for them to provide effective release to the patient, will take quite a long period of about 25 days to one month or may be even more than that. Therefore, they are not very effective. They do not provide long term relief too. Lasers, though they provide long term relief are not without inherent problems. The problems with lasers are that it needs expensive and cumbersome equipment, which will make the treatment all the more expensive for the patient. The laser equipment cannot be afforded by all doctors and thus not found in many clinics. The problem with Iontophoresis are that it is a time consuming procedure and again needs expensive equipment, thus making the overall treatment very expensive. There are some agents which provide quick relief, but such methods necessitates the help of dentists for application. It also requires frequent visits to the dental clinics, which can again be expensive to the patient and not time effective. So, need for developing a treatment procedure, which is not expensive, which has increased contact time, a treatment which can be used by the patient without a doctor% prescription or intervention has been come out with, i.e., over the counter drug. The advantage of such a drug will be that the patient can use it himself, safely and quite effectively. When carbomer is used for the treatment of dentinal hypersensitivity, the drug incorporated into it will be released locally only on to the sensitive site for over a period of 12 to 24 hours or even more, with improved accuracy. As the drug is released directly to the site, the drug required will be of low concentration, thereby reducing the toxicity. The drug is not released into the saliva and hence it can be claimed to be very safe.
Polycarbophil is physiologically inert and is not absorbed by Gastro - Intestinal tract to systemic circulation. Carbomers have been reported to have good muco-adhesive properties by localizing the drug to the site of absorption. These polymers could increase the drug concentration at the absorption sites, thus resulting in enhanced and faster bio-availability. Further, carbomer formulations demonstrate a sustained release. Carbomer appears to be a good disintegrant and directly compressible vehicle. Carbomers produce tablets with excellent hardness and friability over a range of compressive forces. Carbomer can be applied over any tooth in the oral cavity and the added advantage is, it does not hinder the functions like eating, speech, swallowing. Further, the patient can even brush over the pellet and thereby maintain proper oral hygiene, even when the treatment is in progress.
Dentinal Hypersensitivity occurs when dentinal tubules are exposed to external source of irritation like tactile, chemical, osmotic, thermal, coid, evaporative stimuli.
Hydrodynamic Theory is the most accepted theory of sensitivity and was given by Kramer in 1955 and Brannstrom's work in I960, which resulted in wide spread and current acceptance of the theory. According to this theory, the pain is caused by movements of dental lymph - a semi fluid material within the tubules, which convey surface irritation to nerve endings on pulpal surface. So, to prevent dentinal hypersensitivity, the hydrodynamic mechanism has to be blocked. This can be done by blocking the dentinal tubules. There are a variety of agents that could be used to block the dentinal tubules such as oxalates, Calcium hydroxide, fluorides etc., these agents can be delivered by various methods to the sensitive tooth sites like dentifrices, mouthwashes, topical in-office application etc., These agents react with ions in the tooth structure to form crystals on surface of the dentine to be effective. The crystals must be small enough to partially/fully obturate the tubules and reduce permeability of dentinal tubules.
Carbomers are being used extensively in the formulation of muco- adhesive controlled drug delivery systems. These are capable of providing controlled drug release at lower concentrations than other controlled release excipients. Its application as tooth-adhesive in controlled drug delivery system is a new idea of delivering the drug at the targeted site for the treatment of dentinal hypersensitivity, caries, bad breath and like oral conditions. This method would prove to be more efficient and economical than the existing methods.
In this invention A PROCESS OF USING CARBOMER AS A DRUG CARRIER TO THE HARDER TISSUES OF THE ORAL CAVITY, the use of
Carbomers is on a very wide range. Fluorides can be incorporated into the Carbomers, which would greatly enhance the release period of fluoride, which would be optimal for its anti-caries action. Further, carbomers can be used as an intrasulcular drug delivery system after incorporating various therapeutic agents, like antibiotics, antiseptic, anti¬inflammatory agents or redox agents, which would alter periodontal pocket micro flora in a favorable manner. A mouth freshener can be incorporated into the carbomer, which will keep the mouth fresh for long periods. The advantage of using a carbomer as an agent is that it could be used in a compact form and can be applied over any tooth in the oral cavity. The pellet can be self-applied by the patient without the assistance of a professional.
FORMATION OF PELLETS:
Magnesium stearate is the barrier material used and Carbopol/Carbomer is the carrier used to carry and hold the drug or the active ingredient. Potassium oxalate, Strontium chloride, Sodium fluoride, Calcium fluoride, Strontium fluoride or Sodium monofluorophosphate are the agents used for treating dentinal hypersensitivity and are the drugs or the active ingredients for treating dentinal hypersensitivity. Further, these agents can also be used to prevent caries. When their anti-caries action is needed, Magnesium stearate barrier will not be used and thus the drug will be released slowly and continuously into die saliva for long periods. The washing out action of saliva will carry fluorides to all areas of oral cavity.
In both the above cases, flavouring agents can be used to make the drug palatable and to increase patient compliance. For example, a peppermint flavour can be incorporated alone to carbopol/carbomer and in this case the peppermint flavour will be released for long periods into saliva and acts as a mouth freshener. It also increases salivary flow rate, thus increasing washing action of saliva. In this case also, Magnesium stearate barrier is not used.
Magnesium stearate, which is used as a barrier material, prevents the release of the drug into saliva. The barrier material being hydrophobic in nature, reduces salivary contact with drug and the carrier, thus prolonging the time of drug and the carrier retention in the oral cavity. This will greatly enhance the contact time of drug with target site or tissue.
The Magnesium stearate powder is first compressed under pressure to a pellet of about 0.5 to 0.7 mm thick and about 8 mm diameter. The drug (Potassium oxalate or Strontium chloride) is triturated and made into fine powder and is then mixed with the carrier material carbopol under dry conditions as the carrier material is hygroscopic in nature. This mixture of drug and carrier material is then compressed under pressure against the already available Magnesium stearate pellet which will give rise to a single pellet of about 1.3 to 1.7 mm thick or as thin as possible. These agents are used alone or in combination and the pellets will be prepared in the same method, as done when using Potassium oxalate or Strontium chloride.

We claim,
1. A PROCESS OF USING CARBOMER AS A DRUG CARRIER TO THE HARDER TISSUES OF THE ORAL CAVITY, wherein a carbomer is used as a drug carrier, that can stick on to the harder tissues of the oral cavity, used in the form of a pellet, which ensures that the drug is directed towards the target site only and is formed by compressing under pressure the barrier material, i.e., Magnesium stearate in this case to about 0.5 to 0.7 mm thickness and about 8 mm diameter, the drug Potassium oxalate or strontium chloride being triturated and made into fine powder and subsequently mixed with the hygroscopic carrier material, i.e., carbopol under dry conditions; now the readily available mixture of the drug and the carrier material together compressed under pressure against the readied Magnesium stearate pellet, which gives rise to a single pellet of about 1.3 to 1.7 mm thick.